Protective glove with inner glove life indicator

ABSTRACT

An inner indicator glove formed of multiple layers including a protective layer having a top surface and a bottom surface, the bottom surface facing a hand of a user when wearing the inner indicator glove, and an indicator layer supported by the top surface of the protective layer and positioned to contact protective glove when the inner indicator glove is inserted into the protective glove, wherein the indicator layer is formed of a material that changes color when exposed to a solution penetrating the protective glove.

RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. Section119 to European Patent Application Serial No. 15198547.0, filed on Dec.8, 2015, which application is incorporated herein by reference in itsentirety.

BACKGROUND

The protective gloves for process industries (petrochemical, chemical,food, beverage, and pharmaceutical) are constructed to assure peoplesafety under harsh chemical, mechanical and electrical conditions. Theglove suppliers provide a big product catalog, where different types ofgloves are recommended for different type of chemicals to be handled.Depending on the application and chemical products to which they areexposed, the gloves may have a different type of material and adifferent thickness of the layers from which they are made of.

In many countries, such as European countries, the gloves have to passmechanical (EN 388), thermal (EN511), and chemical standards, such as aEuropean standards (EN 374-2, EN 374-3) before they are sent to themarket. In addition to these standards, the gloves should comply withthe standard EN 420, which specifies general criteria for comfort, size,dexterity, labeling, and heavy metal content and pH content. Eachstandard defines exact test and acceptance conditions for the glovesexposed to critical mechanical, thermal, chemical agents. There may bevarious levels of performance specified by the different standards. Forinstance a first level may specify the test and acceptance conditionsfor the least aggressive value of the externally applied agent and thehighest level may be associated with the most aggressive value of theexternally applied agent.

For example, the standard EN-374-2 characterizes the permeabilityfeatures of the gloves and it specifies a method for testing theprotective gloves resistance to permeation of chemical products(penetration). Standard EN374-3 includes the standard. EN 374-2requirements, and in addition, requires that the protective glove passthe performance level 2 of chemical resistance for at least threechemical products (like, methanol, sulfuric acid 96%, 40% sodiumhydroxide, tetrahydrofuran, acetone, carbon disulfide, ethyl acetate,etc.) This performance level 2 for chemical resistance means that thepermeation time (test made according to the standard) should be higherthan or equal to 30 minutes, when the glove is exposed continuously tothat chemical.

A catalog of gloves for chemical protection. during handling of acidsand alkalis, for example, would include as suitable the latex gloveswhich can be used in harsh applications for food and beverage industrywhere cleaning with high concentrated cleaning agents are the most used.Such latex gloves meet the above standard and they are also accompaniedby a wide list of permeation data. Related to the protective glovesdescribed above, their use in the field is made most of the time withoutkeeping clear evidence of the time of use during their lifetime, and soin many cases they can be used for a much shorter time with respect totheir designed lifetime. On the other hand, the suppliers themselves maybe conservative in specifying the level of performance, which means thateven if the real level of performance may be 4, the supplier wouldspecify 3, which is lower than 4. The reason for this conservativeapproach may the fact that according to the standard requirements, thesupplier is testing the resistance of the gloves in 12 families ofchemical agents, each represented by a certain concentration at acertain temperature, while the real breakthrough time of the glove inthe field can be indicated with accuracy only for breakthrough testsperformed in that real agent, at that temperature.

SUMMARY

An inner indicator glove formed of multiple layers including aprotective layer having a top surface and a bottom surface, the bottomsurface facing a hand of a user when wearing the inner indicator glove,and an indicator layer supported by the top surface of the protectivelayer and positioned to contact protective glove when the innerindicator glove is inserted into the protective glove, wherein theindicator layer is formed of a material that changes color when exposedto a solution penetrating the protective glove.

A method of forming an inner indicator glove, the method including dipcoating a hand shaped former into a bath to form a protective-layerhaving a thickness that provides a selected protection time less than aprotection time of a protective glove and forming an indicator layer onthe protective layer, the indicator forming an outer layer of the innerindicator glove.

A method includes inserting an inner indicator glove into a protectiveglove, wherein the inner indicator glove has an indicator layerpositioned to change color responsive to an end of service life of theprotective glove, using the protective glove with the inserted innerindicator glove, viewing the change of color of the indicator layer, anddiscontinuing use of the protective glove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a protective outer glove andinner indicator glove for use inside the protective outer gloveaccording to an example embodiment.

FIG. 2 is a cross section representation of a portion of an innerindicator glove according to an example embodiment.

FIG. 3 is a block diagram of a protective outer glove having atransparent patch for viewing an inner indicator glove color accordingto an example embodiment.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings that form a part hereof, and in which is shown by way ofillustration specific embodiments which may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention, and it is to be understood thatother embodiments may be utilized and that structural, logical andelectrical changes may be made without departing from the scope of thepresent invention. The following description of example embodiments is,therefore, not to be taken in a limited sense, and the scope of thepresent invention is defined by the appended claims.

Suppliers of protective gloves may be conservative in specifying thelevel of performance of the gloves that they sell. Even if the reallevel of performance may be 4, the supplier would specify 3,representing a shorter period of time than the actual performance of theglove prior to failure. A protective glove without any fabricationdefects can still create injury to the user at the unknown end of itsservice life due to the permeation of the dangerous liquid/gases throughthe micro/nano pores of the glove, which can, thus, reach the skin ofthe user.

FIG. 1 is a representation of a protective glove 100 to be used inconjunction with an inner indicator glove 110 that fits inside ofprotective glove 100. The protective glove may be formed of latex orother protective material, like nitrile, chloroprene (e.g. Neoprene,butyl, polyvinyl chloride (PVC), PU, CSM, Fluoro elastomer (e.g. Viton).Off the shelf protective gloves that are unmodified may be used in someembodiment.

In order to obtain a maximum protection of the user's hands even in thesituation of protective glove 100 reaching its (100%) end of servicelife during the working time, the inner indicator glove 110 isintroduced into the outer protective glove (G2G-glove to glove). Theinner indicator glove 110 is designed to indicate the permeation ofharsh chemicals through the outer glove and to assure hand protectionfor a minimum amount of time, such as at least 10 minutes of work(performance level 1).

FIG. 2 is a cross section view of a portion 200 of the inner protectiveglove 110. The inner protective glove 110 in one embodiment is thin andflexible, comprising two layers, a top layer 210 and a bottom layer 220,strongly adhering one to the other, being stacked together during afabrication process. The bottom layer 220 is formed of protectivematerial having a thickness suitable for ensuring protection of a handfor a specified amount of time following failure of the protective glove100, such as 10 minutes. Other times, such as 5 minutes, 15 minutes, orany other time may be selected. Note that the protective bottom layer220 may be quite a bit thinner than the thickness of the protectiveglove 100.

Top layer 210 of the inner indicator glove is made of a material whichchanges its color due to the pH of the liquid permeating through theouter glove. Such a color changing layer can be made of universal pHindicator, and may thus respond to any type of chemical, either acid orbase and its mixture.

A good example for such universal pH indicator is the bromophenol blue.According to the color change of the bromophenol blue exposed to theliquid, a yellow color is obtained for pH smaller than 3, multiplecolors for pH between 3 and 4.6 (real pH indicator in this pH range) andblue color for pH greater than 4.6. The advantage of bromophenol blue isthat it has the largest change in color hue, when the concentration ofthe observed sample increases or decreases. If for example one needs aindicator to be used for the top layer 220 of the inner indicator glove110 immersed only in the acid baths, then one can use a color changinglayer (top layer 220) based on methyl orange (C₁₄H₁₄N₃NaO₃S) whichindicates the presence of acids (pH between 0 and 6), discriminatingvery well the strength of the acid. For other applications, where onlybases are handled, one can have a color changing layer based onphenolphthalein, which is colorless below 8.2 and pink above that valueup to a pH of about 13. For even stronger basic solutions, thephenolphthalein becomes colorless. The bottom layer 220 of the innerglove, which is in contact with the skin, it is made of a chemicallyresistant material like latex, butyl, CSM/neoprene, etc.

Such an inner indicator glove 110 with continuous color change top layer220 above the entire hand has the advantage of identification of thestarting leakage area without any harmful effect of on the skin of theuser, while the outer protective glove itself has been safely usedduring its maximum service life, without any concerns related to its usein the last period of use.

Determining that the inner indicator glove 110 has changed color may bedone in several different ways. In one embodiment, the user may simplyremove the outer protective glove 100 and visually inspect the innerindicator glove 110 for color changes. In a further embodiment, atransparent or at least partially transparent or translucent patch maybe provided on an alternative outer protective glove 300 as indicated at310 in FIG. 3. The patch 310 is sufficiently transparent to allow a userto see the color of the inner indicator glove without removing the outerglove.

In a still further embodiment, the activation mechanism causing theinner indicator glove to produce a visible indication results in a flowof an indicator solution comprising vapors and liquids the externalglove is exposed to, to an external surface of the protective glove. Inthe body of the protective gloves there are always nanopores which arefilled with air, and these nanopores are at the origin of the liquidpermeation process. This means that the liquid molecules can diffuseinside the protective glove via those pores and after a certain timethey can penetrate the entire thickness of the protective glove,reaching the inner indicator glove. This time is called the breakdowntime of the protective glove in a certain solution. The breakdown timeof a protective glove will depend on its thickness, the magnitude of thepermeating liquid molecule and the size of the nanopores. Exposure ofthe protective glove to the solution results in nanopores filling withliquid molecules, and thus the liquid gradually penetrates theprotective glove. After the nanopores are filled with the solution alongthe entire thickness of the protective glove, the solution from thenanopores will start to dissolve the color changing indicator layer 210containing bromophenol blue in one embodiment in the inner indicatorglove 110, acting as a pH indicator or dye. This dye will startdiffusing back along the nanopores via concentration gradient andcapillary forces, through the protective glove 100 until visible at theouter surface of the protective glove 100.

When the dye arrives at the outer surface of protective glove 100through a multitude of nanopores, a change in the background color ofprotective glove will be easily visible to a user. A background color ofwhite for the protective glove 110 may provide for maximum contrast ofthe indication color. The color will be changed according to the overallpH of the liquid in the pores after glove exposure to both acids andbases, and solvents, i.e., the solution.

Three fabrication processes for the inner indicator glove are described,where a solid state pH indicator layer is deposited continuously on theentire chemically resistant layer of the inner indicator glove.

The first fabrication process is similar to a traditional dip coatingprocess used for the protective glove. A second process is a hybridapproach where the chemically resistant layer is made by dip coatingwhile the color changing layer is made by direct printing. The thirdprocess is an all-printing process, where both color changing layer andthe chemically resistive layer are made by a method of direct printing.This G2G concept can be applied to all types of chemically protectivegloves. Moreover, a universal inner indicator glove can be used for alltype of gloves dedicated to acid/base/solvent combinations.

Generic standard technology for the dip coating fabrication process ofthe protective gloves consists of full immersion of a hand shaped former(HSF) in multiple baths where the liquid state of the future layers arepresent. In one embodiment, the hand shaped former is in the shape of atypical glove, having portions corresponding to an arm, palm area, fourfingers and a thumb. Different HSFs may be used for each hand andmultiple HSFs may be used of varying sizes corresponding to differentsizes of hands and protective gloves. After each dip coating, a thermaltreatment is made for the solid state consolidation of the film. At theend of the process, the gloves are peeled off from the HSF, and thus thelast deposited layer on the glove will be the layer in contact with theskin. Note that in some embodiments, the glove is not reversed whenpeeling it off from the HSF, or may be turned inside out after peelingoff. This allows the inner indicator glove to be formed by first formingthe latex protective layer followed by the indicator layer.

Note that in some embodiments, the same size HSF may be used to formboth the protective glove 100 and the inner indicator glove 110 suchthat a tight fit of the inner indicator glove 110 into the protectiveglove 100 is obtained. A tight fit ensures better tactile feel anddexterity for the user in utilizing the combined gloves. A tight fit mayalso promote better migration of color from the inner indicator glove tothe outside of the protective glove for viewing by a user. In furtherembodiments, a slightly smaller size HSF may be used for the innerindicator glove formation.

Three alternative methods for making inner indicator glove 110 aredescribed.

I. An example of a “standard” all-dip-coating fabrication process of asmart latex inner indicator glove 110 containing a color change layer210 as follows:

1. Dip coating of the hand-shape former (HSF) into the “latex” bath forgetting a latex film of the desired thickness.

2. Thermal treatment of the dip-coated HSF for obtaining a solid stateof the thin latex film.

3. Dip-coating of the HSF from step 2 into a bath containing bromophenolblue slurry at the right viscosity.

4. Thermal treatment of the HSF from the step 3.

II. An example of the original hybrid fabrication process of smart innerindicator glove 110 based on dip-coating and direct printing may beperformed as follows:

1. Dip coating of the hand-shape former (HSF) into the “latex” bath forgetting a latex film of desired thickness. (about 20% of the thicknessof the outer glove).

2. Thermal treatment of the dip-coated HSF from step 1 for obtaining asolid state of the first latex film.

3. Direct printing of the color changing layer. Direct printing, such asby inkjet printer allows the color changing layer to be masklesslydeposited.

4. Thermal treatment of the HSF from step 3 which was direct printed forgetting a solid color changing layer.

III. Finally, an example of original all-printed inner indicator glove110 may also utilize direct printing to replace all the dip-coatingprocesses from above.

An example of process for making the viscous bromophenol blue slurrythat can be used for dip coating or inkjet printing can be as shownbelow:

1. Dissolve the bromophenol blue powder in a mixture of water and smallamount of solvent like ethylic alcohol, dimethylformamide, ordimethylsulfoxide.

2. Add surfactants like Tween 20, Tween 40, Tween 60, Tween 80.

3. Add viscosity intensifying agent resin (like shellac, guaiac gummethyl cellulose and ethyl cellulose).

4. Obtain a homogeneous and viscous solution of the color changing agentbased on bromophenol blue.

An automated factory for fabrication of all printed inner indicatorgloves utilizing moving the HSF on a line from one location to another,and at each location, the HSF will receive the required process asdescribed above. For thermal treatment the HSF can travel through afurnace with the required temperature profile, as required by theprevious printed layer.

EXAMPLES

1. An inner indicator glove fanned of multiple layers comprising:

-   -   a protective layer having a top surface and a bottom surface,        the bottom surface facing a hand of a user when wearing the        inner indicator glove; and    -   an indicator layer supported by the top surface of the        protective layer and positioned to contact protective glove when        the inner indicator glove is inserted into the protective glove,        wherein the indicator layer is formed of a material that changes        color when exposed to a solution penetrating the protective        glove.

2. The inner indicator glove of example 1 wherein the change in colorbecomes visible from an external surface of the protective glove whenthe inner indicator glove is inserted into the protective glove.

3. The inner indicator glove of any of examples 1-2 wherein the changein color becomes visible when a least a portion of the inner indicatorglove is removed from the protective glove.

4. The inner indicator glove of any of examples 1-3 wherein theindicator layer comprises a pH indicator generating a colorcorresponding to a pH of the solution.

5. The inner indicator glove of example 4 wherein the pH indicatorcomprises bromophenol blue.

6. The inner indicator glove of any of examples 1-5 wherein theprotective layer comprises natural or synthetic lattices.

7. The inner indicator glove of any of examples 1-6 wherein theindicator layer is a continuous layer.

8. The inner indicator glove of any of examples 1-7 wherein theprotective layer comprises at least one of latex, nitrile, orchloroprene and the indicator layer comprises bromophenol blue.

9. The inner indicator glove of any of examples 1-8 wherein theprotective layer has a thickness configured to provide approximately 10minutes of protection when the life of the protective glove has failedand the indicator layer changes color responsive to the failure of theprotective glove.

10. The inner indicator glove of any of examples 1-9 and furthercomprising a protective glove into which the indicator glove has beeninserted.

11. The inner indicator glove of any of examples 1-10 wherein theprotective glove includes a transparent patch through which the color ofthe indicator layer is observable.

12. A method of forming an inner indicator glove, the method comprising:

-   -   dip coating a hand shaped former into a bath to form a        protective-layer having a thickness that provides a selected        protection time less than a protection time of a protective        glove; and    -   forming an indicator layer on the protective layer, the        indicator forming an outer layer of the inner indicator glove.

13. The method of example 12 wherein forming an indicator layer on theprotective layer comprises dip coating the hand shaped former having thefirst protective layer into a bath containing a bromophenol blue slurryto form the indicator layer comprising bromophenol blue.

14. The method of example 13 wherein the bromophenol blue slurrycomprises bromophenol blue powder, alcohol, a surfactant, and aviscosity intensifying agent resin.

15. The method of any one of examples 12-14 wherein forming an indicatorlayer on the protective layer comprises printing the indicator layer.

16. A method comprising:

-   -   inserting an inner indicator glove into a protective glove,        wherein the inner indicator glove has an indicator layer        positioned to change color responsive to an end of service life        of the protective glove;    -   using the protective glove with the inserted inner indicator        glove;    -   viewing the change of color of the indicator layer; and    -   discontinuing use of the protective glove.

17. The method of example 16 wherein viewing the change of color of theindicator layer comprises removing a portion of the protective glove toexpose the inner indicator glove such that the change of color isvisible to a user.

18. The method of example 16 wherein viewing the change of color of theindicator layer comprises viewing a solution that diffused back throughnanopores in the protective glove to an outer surface of the protectiveglove, the solution being colored by the indicator layer responsive tothe solution penetrating the protective glove signifying the end of theservice life of the protective glove.

19. The method of example 16 wherein viewing the change of color of theindicator layer comprises viewing the indicator layer through atransparent patch of the protective glove.

20. The method of example 16 wherein the indicator layer comprisesbromophenol blue.

Although a few embodiments have been described in detail above, othermodifications are possible. For example, the logic flows depicted in thefigures do not require the particular order shown, or sequential order,to achieve desirable results. Other steps may be provided, or steps maybe eliminated, from the described flows, and other components may beadded to, or removed from, the described systems. Other embodiments maybe within the scope of the following claims.

1. An inner indicator glove formed of multiple layers comprising: aprotective layer having a top surface and a bottom surface, the bottomsurface facing a hand of a user when wearing the inner indicator glove;and an indicator layer supported by the top surface of the protectivelayer and positioned to contact protective glove when the innerindicator glove is inserted into the protective glove, wherein theindicator layer is formed of a material that changes color when exposedto a solution penetrating the protective glove.
 2. The inner indicatorglove of claim 1 wherein the change in color becomes visible from anexternal surface of the protective glove when the inner indicator gloveis inserted into the protective glove.
 3. The inner indicator glove ofclaim 1 wherein the change in color becomes visible when a least aportion of the inner indicator glove is removed from the protectiveglove.
 4. The inner indicator glove of claim 1 wherein the indicatorlayer comprises a pH indicator generating a color corresponding to a pHof the solution.
 5. The inner indicator glove of claim 4 wherein the pHindicator comprises bromophenol blue.
 6. The inner indicator glove ofclaim 1 wherein the protective layer comprises natural or syntheticlattices.
 7. The inner indicator glove of claim 1 wherein the indicatorlayer is a continuous layer.
 8. The inner indicator glove of claim 1wherein the protective layer comprises at least one of latex, nitrile,or chloroprene and the indicator layer comprises bromophenol blue. 9.The inner indicator glove of claim 1 wherein the protective layer has athickness configured to provide approximately 10 minutes of protectionwhen the life of the protective glove has failed and the indicator layerchanges color responsive to the failure of the protective glove.
 10. Theinner indicator glove of claim 1 and further comprising a protectiveglove into which the indicator glove has been inserted.
 11. The innerindicator glove of claim 1 wherein the protective glove includes atransparent patch through which the color of the indicator layer isobservable.
 12. A method of forming an inner indicator glove, the methodcomprising: dip coating a hand shaped former into a bath to form aprotective-layer having a thickness that provides a selected protectiontime less than a protection time of a protective glove; and forming anindicator layer on the protective layer, the indicator forming an outerlayer of the inner indicator glove.
 13. The method of claim 12 whereinforming an indicator layer on the protective layer comprises dip coatingthe hand shaped former having the first protective layer into a bathcontaining a bromophenol blue slurry to form the indicator layercomprising bromophenol blue.
 14. The method of claim 13 wherein thebromophenol blue slurry comprises bromophenol blue powder, alcohol, asurfactant, and a viscosity intensifying agent resin.
 15. The method ofclaim 12 wherein forming an indicator layer on the protective layercomprises printing the indicator layer.
 16. A method comprising:inserting an inner indicator glove into a protective glove, wherein theinner indicator glove has an indicator layer positioned to change colorresponsive to an end of service life of the protective glove; using theprotective glove with the inserted inner indicator glove; viewing thechange of color of the indicator layer; and discontinuing use of theprotective glove.
 17. The method of claim 16 wherein viewing the changeof color of the indicator layer comprises removing a portion of theprotective glove to expose the inner indicator glove such that thechange of color is visible to a user.
 18. The method of claim 16 whereinviewing the change of color of the indicator layer comprises viewing asolution that diffused back through nanopores in the protective glove toan outer surface of the protective glove, the solution being colored bythe indicator layer responsive to the solution penetrating theprotective glove signifying the end of the service life of theprotective glove.
 19. The method of claim 16 wherein viewing the changeof color of the indicator layer comprises viewing the indicator layerthrough a transparent patch of the protective glove.
 20. The method ofclaim 16 wherein the indicator layer comprises bromophenol blue.